Analysis of Level-Off Flight Segments of Descending Aircraft for Busy Terminal Maneuvering Areas

The demand for air transportation increases significantly worldwide, and the number of aircraft and passengers is also rising. This situation directly affects the major airports and their surrounding Terminal Manoeuvring Areas (TMAs) because they launch new destinations and increase flight frequency. However, airport and airspace structures have some difficulty meeting this increasing demand. Therefore, there is an increase in airborne delay in air traffic congestion. Airborne delay severely affects TMAs operations since they have several entry points, yet all arrival traffic lands mainly at the same airport. This problem also expands the flight duration within TMAs. Air traffic controllers regulate the arrival traffic with separation and sequencing methods, including vectoring, point merge approach or holding manoeuvres. These are generally implemented at a constant flight level. Therefore, they generate level-off flight segments during the descending profile of arrival aircraft. The level-off segments directly increase the fuel consumption and emissions values because of engine configurations. Therefore, this study aims to expose the level-off segments for the London Heathrow, Amsterdam Schiphol, Paris Charles de Gaulle and Istanbul airports. The results show that Amsterdam Schiphol has the lowest level-off time to total descent time ratio of 12.8% among other airports.